Numerous ethylene-bis-dithiocarbamate products exist which have proven commercial value as protective fungicides. The more commercially important of these include nabam, zineb, maneb and mancozeb. All of these products contain varying amounts of ethylene thiourea which is produced during the manufacturing process and on long term storage. Various processes for stabilizing these products have been developed over the years with mixed success. Such stabilization processes have included the addition of hexamethylene tetramine or paraformaldehyde and/or various washes to remove the impurity at various steps in the manufacturing process. U.S. Pat. No. 3,379,610 granted Apr. 23, 1968 discloses a mixed manganese, zinc, cobalt metal salt complex of ethylene-bis-dithiocarbamic acid but does not specifically disclose the copper modified mancozeb of the present invention nor does it recognize the unique ability of the product of this invention to chemically stabilize ethylene-bis-dithiocarbamic acid. The Journal of Agriculture and Food Chemistry, Vol. 28, 787-790 (1980) discloses that soluble copper(II) ion stabilizes maneb and decreases the formation of ethylene thiourea to trace amounts when high weight ratios of copper sulfate to maneb (ten fold excess) are utilized. Various combinations of mancozeb with insoluble copper salts such as copper oxychloride, copper hydroxide, copper carbonates and basic copper sulfates are known. The South Africa Pat. No. 660,165 published July 15, 1966 discloses products formed from the reaction of ethylene-bis-dithiocarbamate sodium salt with mixtures of copper, manganese and zinc sulfates wherein the ratio of copper:manganese:zinc is 1.07:1.22:1.79.